whatis

whatis linux command cheatsheet by Thamizhiniyan C S

Introduction

The whatis command is used to display one-line manual page descriptions.

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Syntax

whatis [-dlv?V] [-r|-w] [-s list] [-m system[,...]] [-M path] [-L locale] [-C file] name ...

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Important Flags

Flag	Description
-d, --debug	Emit debugging messages.
-v, --verbose	Print verbose warning messages.
-r, --regex	Interpret each keyword as a regex.
-w, --wildcard	The keyword(s) contain wildcards.
-l, --long	Do not trim output to terminal width.
-C, --config-file=FILE	Use this user configuration file.
-L, --locale=LOCALE	Define the locale for this search.
-m, --systems=SYSTEM	Use manual pages from other systems.
-M, --manpath=PATH	Set search path for manual pages to PATH.
-s, --sections=LIST, --section=LIST	Search only these sections (colon-separated).
-?, --help	Give this help list.
--usage	Give a short usage message.
-V, --version	Print program version.

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Examples

Command	Description
whatis -h	Prints the help message.
whatis -d ls	Prints the debugging information.
whatis -v ls	Prints verbose warning messages.
whatis -r ls	Supports regular expression searches.
whatis -r '^ab'	Searches and displays short descriptions of commands and functions matching the regular expression '^ab'.
whatis -r '^cd'	Searches and displays short descriptions of commands and functions matching the regular expression '^cd'.
whatis -r 'cd$'	Searches and displays short descriptions of commands and functions matching the regular expression 'cd$'.
whatis -w ls	Enables wildcard searches using the specified pattern.
whatis -w 'ab*'	Searches and displays short descriptions of commands and functions matching the wildcard pattern 'ab*'.
whatis -w 'cd*'	Searches and displays short descriptions of commands and functions matching the wildcard pattern 'cd*'.
whatis -l cat	Displays long descriptions in addition to the summary.
whatis -s 3 cat	Allows users to specify the sections from which to retrieve the information. By default, it searches all sections.
whatis -s "1","2" cat	Accesses information from sections 1 and 2 of the manual page for the cat command.
whatis -m NewOS rmdir	Accesses manual page names for other operating systems.
whatis -m OS2 rmdir	Accesses the short description of the rmdir command from the OS2 manual pages.
whatis cd -M --manpath=/lib/cd	Specifies an alternate set of colon-delimited manual page hierarchies to search. It overrides the default value of the $MANPATH environment variable.
whatis rm -L locale	Temporarily overrides the determined locale value, allowing users to supply a locale string directly to the 'whatis' command.
whatis -C file	Specifies a user configuration file for the 'whatis' command, overriding the default configuration file location ~/.manpath.
whatis -?	Prints a help message.
whatis --usage	Displays short information about the whatis command and exits.
whatis -V	Displays version information.
whatis ssh-import-id	Displays the trimmed output of the ssh-import-id command.